For many personal care absorbent articles, medical absorbent articles, and the like, it is desirable to reduce, prevent, or eliminate odors during use. For diapers and other incontinence products, it is desirable to reduce or eliminate the odor of ammonia which is present in urine. For feminine hygiene products, it is desirable to reduce or eliminate the odors of trimethylamine and triethylamine. Other common odor-producing substances include isovaleric acid, dimethyl disulfide, and dimethyl trisulfide.
Odor control agents include odor inhibitors, odor absorbers, odor adsorbers and other compounds which suppress odors. Odor inhibitors prevent the odor from forming. For example, U.S. Pat. No. 4,273,786 to Kraskin teaches the use of an aminopolycarboxylic acid compound for inhibiting the formation of ammonia from urea in urine. Odor absorbers and adsorbers remove odor after it is formed. Examples of odor control agents that remove odor by absorption or adsorption include activated carbon, silica, and cyclodextrin.
Acidic odor control agents based on carboxylic acids and their derivatives are used to neutralize or inhibit formation of odors from ammonia and other basic odor-forming compounds. Ammonia, released from aqueous ammonium hydroxide, is one of the primary odor-producing substances in urine. One of the drawbacks of acidic odor control agents is they are not inherently durable, i.e., they pass into solution after one or more insults with aqueous liquid, and may acidify the liquid. If some of the acidified aqueous liquid leaks from the absorbent article and passes to the wearer's skin, the wearer may experience itching, rash, and/or other uncomfortable effects.
Previously, acidic odor control agents have been applied to absorbent articles in the form of powders, coatings, and the like, which can be easily dissolved. There is a need or desire for absorbent articles having durable acidic odor control agents, which retain their odor control functions and do not pass into solution after one or more insults with aqueous liquid.